Added methods for removing subclasses -- couldnt make it work with the regular nested-module approach (ObjectSpace was being difficult), so this is a straight inclusion

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@506 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/lib/core_ext/object_and_class.rb

@@ -0,0 +1,24 @@
+class Object #:nodoc:
+  def remove_subclasses_of(superclass)
+    subclasses_of(superclass).each { |subclass| Object.send(:remove_const, subclass) rescue nil }
+  end
+
+  def subclasses_of(superclass)
+    subclasses = []
+    ObjectSpace.each_object(Class) do |k|
+      next if !k.ancestors.include?(superclass) || superclass == k || k.to_s.include?("::") || subclasses.include?(k.to_s)
+      subclasses << k.to_s
+    end
+    subclasses
+  end
+end
+
+class Class #:nodoc:
+  def remove_subclasses
+    Object.remove_subclasses_of(self)
+  end
+
+  def subclasses
+    Object.subclasses_of(self)
+  end
+end

activesupport/test/core_ext/object_and_class_ext_test.rb

@@ -0,0 +1,21 @@
+require 'test/unit'
+require File.dirname(__FILE__) + '/../../lib/core_ext/object_and_class'
+
+class A; end
+class B < A; end
+class C < B; end
+class D < A; end
+
+class ClassExtTest < Test::Unit::TestCase
+  def test_methods
+    assert defined?(B)
+    assert defined?(C)
+    assert defined?(D)
+
+    A.remove_subclasses
+
+    assert !defined?(B)
+    assert !defined?(C)
+    assert !defined?(D)
+  end
+end